Even though agricultural harvesting has been automated in many cases, the picking of objects such as wine grapes in a vineyard is still very often a manual operation. Handpicked grape clusters are placed by the worker into relatively small boxes termed lugs. When a lug is filled, it is carried to a location in the field row where each grape cluster is placed into a fenestrated plastic bag. The filled bags are then loaded into boxes for transport to storage or the marketplace. Generally, similar manual systems are used to harvest and collect strawberries, cherries, and other fruits and agricultural produce. Indeed, generally similar manual systems are used to collect and transport a wide variety of agricultural and industrial objects.
Fenestrated bags for handling and storing grapes, cherries, strawberries and other fruits, produce items and other objects are disclosed in U.S. Pat. No. 6,045,838. Fresh produce bags and lugs are disclosed in U.S. Pat. Nos. 5,458,899 and 5,919,504. Other thin flexible plastic bags are commonly provided, free of charge, in the produce sections of many retail grocery stores. Currently such bags are produced from various known plastics such as polypropylenes or mixtures of polyethylenes. If desired, slits or small holes, termed micropores, can be formed in the bag sides to permit sulfur dioxide or other gases to be introduced into the bag interiors to preserve grape freshness while minimizing water loss from the grapes. These preservative gases gradually escape through the bag fenestrations over a period of time (usually hours or days) and are replaced by ambient air.
When a grossly irregularly shaped object such as a cluster of grapes or cherries is presented to the open end of a pneumatic tube, it does not necessarily advance down the pneumatic tube due to the fact that an incomplete and relatively ineffective air seal is present between the interior of the tube or tube baffles and the object. The object's irregular shape allows for the passage of air between the object and the interior of the tube or, in the case of a grape cluster, through the air gaps between individual grapes. Because there is little or no air pressure differential across the grape cluster or other irregularly shaped object to be transported, the small suction force acting on the object is insufficient to cause the object to move down the tube in a positive and regular manner. The objects to be transported can be fruits such as grapes, strawberries, raspberries, blueberries, or cherries; or other agricultural or nonagricultural objects can be enclosed within the bags.